[Mono-list] VBNC in Mono.

Rolf Bjarne Kvinge rolflists at ya.com
Thu Sep 14 14:13:56 EDT 2006


On Thu, 14 Sep 2006 17:22:34 +0200, Jonathan Gilbert  
<2a5gjx302 at sneakemail.com> wrote:

> In the case of an Object that is known to contain a String, a call to
> .ToString() may perform better than a direct cast. A cast still needs to
> check the type, even though the code has already just done it with a  
> TypeOf
> (I'd be very surprised if the JIT can detect that pattern and only do one
> check). Calling .ToString() will be a virtual call to "return this;".  
> It'd
> be interesting to do a comparison, but my intuition is that .ToString()
> would be significantly faster in this case.

Just tried it, but I got inconclusive results (sometimes .ToString()  
performed better, sometimes DirectCast performed better). During the first  
test runs .ToString() did perform better (5-10% better), then suddenly  
DirectCast started performed better (5-20% better), so I don't really  
think there is any big difference. I tried running with and without  
debugger, DEBUG and RELEASE builds, and with and without integer checks  
on, and always got inconclusive results (only on MS, I don't know how Mono  
will perform).

Rolf

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